For super-powered smart
phones, battery life is kryptonite. All that 3G Wi-Fi GPS wonderfulness
leaves batteries exhausted, especially after they've starved themselves thin to
fit into the sexy form factor.

Enter the Mophie Juice Pack, a rechargeable lithium polymer
battery that says it will add up to an additional six hours of talk or surfing
time to the iPhone.

It's a green and black shell that cradles your iBaby
in a soft, almost rubbery grip, like a friendly alien face-hugger. We found it
comfortable to hold and handle, although it added about a centimetre of
thickness to the phone, so it wouldn't suit someone with tiny hands.

It has pass-through USB for syncing and charging, which is very handy,
because you can charge and sync your iPhone with a standard mini USB cable -- of
which we have dozens in our drawers -- rather than carrying around the iPhone's
proprietary one.

We have a theory that the Juice Pack is made of Higgs
bosons -- it has an odd relationship with gravity. At 75g, it feels light
as a feather, but it when it docks with the 135g iPhone 3G, their combined
mass is extremely hefty. We wouldn't want to carry it in our pocket for a night out -- its weight would ruin the line of our silk smoking jacket.

But the Juice Pack is a great
accessory for a long road trip. We would have loved it while roaming Cornwall last weekend, draining
our iPhone's life force with Google Maps and surfing the Web for the best local
pint -- especially when we ended up stranded on the hard shoulder praying the battery would hold up until the RAC called.